1. Kentland Quarry & Kentland, Indiana Impact Structure.
Sat., 4 May, 8 a.m.–6 p.m. Cost: US$115; includes field trip guide, transportation, lunch, and refreshments.
John Weber, Grand Valley State Univ., weberjgvsu.edu.
This structural feature was discovered circa 1880 when two farmers began to quarry crushed rock from the site. The crater is a circular dome, ~7.24 km (4.5 mi) in diameter. It is deeply eroded and buried by glacial debris. Age is estimated to be less than 97 million years (Cretaceous or younger). Shatter cones and deformed bedrock led geologists to conclude by the late 1960s that the Kentland structure was the result of a meteorite impact rather than volcanic activity. Deformation at the site is intense. Vertical contacts between normally horizontal rock formations of different ages are common. The Shakopee dolomite at the center of the structure is ~450 million years old (Ordovician period) and is uplifted ~2,000 feet higher than the level of the same rock in the surrounding area. The entire disturbed area extends about 13 km (8 mi) in diameter.
2. The Detroit Salt Mine.
Sat., 4 May, 8 a.m.–6 p.m. Cost: US$105; includes field trip guide, transportation, lunch, and refreshments.
William B. Harrison III, Michigan Geological Repository for Research and Education (MGREE), harrisonwmich.edu;
E.Z. Manos (on-site leader), Detroit Salt Mine Company.
This is a great opportunity to visit, examine, and collect samples from a working underground salt mine. This mine has been in operation for more than 100 years and currently supplies road salt to many Michigan counties and other areas throughout the Midwest. Silurian salts have been mined in the Michigan Basin since the late 1800s. Both underground and much deeper solution salt mining has taken place. The Silurian F salt bed is being mined at the Detroit Salt mine; whereas, most solution mining has exploited the Salina A and B units. This popular trip is limited to 16 participants, so be sure to reserve your place early.
3. Contrasting Terrains of the Lake Michigan and Saginaw Lobes in Southern Michigan.
Sat., 4 May, 8 a.m.–6 p.m. Cost: $125; includes field trip guide, transportation, lunch, and refreshments.
Alan Kehew, Western Michigan Univ., alan.kehewwmich.edu; Andrew Koslowski, New York State Museum–Albany, akozlowsmail.nysed.gov; Brian Bird, New York State Museum, bbirdnysed.gov; John Esch, Michigan Dept. of Environmental Quality, eschjmichigan.gov.
Recent mapping through the USGS STATEMAP, EDMAP, and Great Lakes Geologic Mapping Coalition programs is leading to new interpretations of the dynamics, drainage, and stratigraphy of the Lake Michigan and Saginaw Lobes of the Laurentide Ice Sheet. The Lake Michigan Lobe most likely readvanced into a proglacial lake, producing extensive glaciotectonic deformation of the glaciotectonic sediment it was overriding. As it retreated from its maximum extent, it was fronted by an extensive proglacial lake into which a variety of proximal glaciolacustrine sediments were deposited. The Saginaw Lobe stagnated over a broad marginal area during its retreat and developed an efficient glacial drainage system with deeply incised tunnel valleys, many of which contain eskers. The trip will spend about half a day looking at the landforms and sediments of each lobe.
4. Pennsylvanian Fluvial-Deltaic Depositional Systems in Central Lower Michigan: Sedimentology, Stratigraphy, and Hydrogeology of the Saginaw Aquifer.
Sat., 4 May
5. Michigan Sand Dunes.
Sat., 4 May, 7 a.m.–7 p.m. Cost: US$125, includes field trip guide, transportation, lunch, and refreshments.
Edward Hansen, Hope College, hansenhope.edu.
The sand dunes along the Lake Michigan shore are among the largest freshwater dune complexes in the world. They have played a critical role in the development of scientific ideas about coastal dunes beginning with Henry Chandler Cowles pioneering work on ecological succession in the late 19th century. During the last 15 years there has been a revival of interest in Lake Michigan dunes that has resulted in a better understanding of both their geomorphic history and the contemporary processes shaping them. This field trip will highlight these new insights while examining a strip of the Lake Michigan coast in southeast Michigan from PJ Hoffmaster State Park north of Grand Haven to the Saugatuck Harbor Natural Area at the mouth of the Kalamazoo River.
6. Geology and Slope Stability along the Lake Michigan Coastal Zone.
Sat., 4 May
7. Spouse/Guest Trip to Frederik Meijer Gardens and Sculpture Park in Grand Rapids.
Sat., 4 May